There have been some very good discussions of this question on here; the search function is your friend. There has been some detailed information posted from very experienced high latitude sailors including Evans Starzinger and others.

I'm going through a somewhat similar question myself, and it looks to me that there is not a clear best solution.

Hydronic heaters require service and electrical power and will shut themselves down if they don't like something. But vastly easier to install with no vertical stack required, and circulate heat best. If you need heat down in your hulls (and you will) then this is by far the most effective way to do that. They also make domestic hot water -- a big plus.

Pot heaters are very simple and easily serviceable, no electrical power. But need a vertical stack and may spread soot on your sails, rigging, deck. The might make domestic hot water and possibly power some radiators if you add coils -- don't know how effective that is. Pot heaters are probably the most popular choice among real high latitude adventure sailors.

There are combo heaters galley stoves as used on Alaskan fishing boats which could be a good solution.

Hot air has all the disadvantages of hydronic but with less effective distribution of heat, plus more noise.

Heat is life or death in the Arctic, so I would probably have redundant systems.

Maybe one pot heater and one hydronic. Put the pot heater in the salon and use the hydronic to heat the cabins in the hulls.

Hydronic furnaces aren't all that expensive and it could be worth having two of them, maybe one small and one large. It's bad for them to run them continuously at low output, so using the small one for low demand conditions could reduce problems, and having two adds some redundancy.

Another great thing about hydronic systems is you can connect them to main engine(s) with heat exchangers and run the heat off engine waste heat. In the Arctic you'll be motoring a lot so this could be a really big plus, saving fuel and wear and tear on the furnaces.

Another tip for hydronic furnaces: If you include a day tank in your design of the system, you can run some kerosene (paraffin, jet fuel) through it from time to time, which is supposed to greatly extend the service interval by burning off the soot.

I've already used search and read pretty much everthing can get my hands on regarding the topic. Now looking for direct input from Cat owners.

I'm not sure why this would be different on a Cat, hence the question. however, a couple spring to mind.

There is for sure different heat dissipation and airflow on a cat to a monohull. I'd think heating it would require a different setup. There is also not a single larger engine room to mount a boiler, or a reflex heater etc.

Right now I'm thinking Hydronic, so my question was probably more to exactly which model. I have no experience on which to Judge a Webasto over a Kabolo, over the one Lagoon fit as standard (if you ask for it).

Related: Any highly recommended after market installers in northern Europe for heating ?

PS: Your right on motoring vs Sailing, there will be more of it when navigating in shore. However I'm expecting a LOT of time sitting at Anchor in a couple locations, with the possibility of overwintering in one.

I've already used search and read pretty much everthing can get my hands on regarding the topic. Now looking for direct input from Cat owners.

I'm not sure why this would be different on a Cat, hence the question. however, a couple spring to mind.

There is for sure different heat dissipation and airflow on a cat to a monohull. I'd think heating it would require a different setup. There is also not a single larger engine room to mount a boiler, or a reflex heater etc.

Right now I'm thinking Hydronic, so my question was probably more to exactly which model. I have no experience on which to Judge a Webasto over a Kabolo, over the one Lagoon fit as standard (if you ask for it).

Related: Any highly recommended after market installers in northern Europe for heating ?

PS: Your right on motoring vs Sailing, there will be more of it when navigating in shore. However I'm expecting a LOT of time sitting at Anchor in a couple locations, with the possibility of overwintering in one.

Regards

OK, cool, good luck with your installation and let us know how it goes. We'll be interested.

I can recommend Kruger in the Southampton area, main dealers for Eber and (I think) Webasto and with very high level of technical skill. They are not cheap, but it's worth it. In general, all this kind of work is best done in the UK -- the biggest concentration of skilled marine trades in the world is in the Solent area. Cowes is particularly good because cost of skilled labor is somewhat less on the Island.

Others will chime in, but I have no information that there is any difference in reliability or function between the main hydronic brands. They all have the same advantages and are subject to the same problems, as far as I know. Mine is Eberspaecher.

A hydronic furnace takes remarkably little space and you shouldn't have any problem finding room for it. Likewise, it is very easy to pull the piping to distribute the heat. It's just 10mm domestic plastic pipe with plastic connectors.

For a pot heater, however, like a Refleks -- you don't need engine room space. You mount those in your main salon on a bulkhead, or free standing. If you can afford it, I would do both, and don't forget about the main engine heat exchanger.

Good luck. Where in the Arctic are you planning to go? We're thinking about White Sea, Barents Sea, Svalbard next year, circumnavigating Fenno-Scandia via St. Petersburg and the White Sea canal.

Interesting. The answer I got from lagoon was uninspiring. Quote "We fit a boiler Eberspacher 12000W/12V." I can't find anything that matches on the Eberspacher website.

I would of assumed it needed to be fitted when built for ease, but perhaps not.

We are planning Svalbard, Iceland, and if that works out, Greenland. I've been to Svalbard several times, and it is an amazing place. Just not on my own boat !. Heading to northern Iceland (by air) again in March and that will be trip num 9.

Note: I have to finish buying the boat first, as per all my other threads ! So we are a ways off this.

The Core decision I'm trying to make is. Do I let Lagoon fit the heating when I order, or do I get someone else to do it aftermarket. And if so, which one. Leaning heavily towards after market !!.

Just as important as the type/brand of heater you choose is the amount of insulation, especially with a cat and the Artic air flowing under your bridge deck. You will need to install some sort of insulation anywhere/everywhere you have access to the skin. If you don't, you will have a very difficult time trying to keep it warm regardless of the heater you will also have tremendous issues with condensation without insulation on the skin. Most cats that I have been on just have some sort of carpet glued to the fiberglass, which is adequate in temperate climates but not so much in cold climates.

Interesting. The answer I got from lagoon was uninspiring. Quote "We fit a boiler Eberspacher 12000W/12V." I can't find anything that matches on the Eberspacher website.

I would of assumed it needed to be fitted when built for ease, but perhaps not.

We are planning Svalbard, Iceland, and if that works out, Greenland. I've been to Svalbard several times, and it is an amazing place. Just not on my own boat !. Heading to northern Iceland (by air) again in March and that will be trip num 9.

Note: I have to finish buying the boat first, as per all my other threads ! So we are a ways off this.

The Core decision I'm trying to make is. Do I let Lagoon fit the heating when I order, or do I get someone else to do it aftermarket. And if so, which one. Leaning heavily towards after market !!.

Regards

Maybe see you up there somewhere!

I would probably let Lagoon fit it if I were you unless you hear reports that they do it badly. They will have a better chance of integrating the pipework and wiring and so forth into the other elements of the boat.

What they are telling you is that they fit a 12kW hydronic boiler. I don't know that model, but Eberspacher have a lot of different ones. Mine is the 10kW version. It sounds ok to me. Do they use radiators or fan coils? That's an important question. Fan coils (like I have) are easier to conceal, and help circulate the heat because the blow air around, but make noise and use electrical power. If you can find room for radiators of adequate capacity -- could be better.

And I would really think about the Refleks or whatever pot heater in the salon. They can be had with glass doors so you can look at a cheery fire while you sit in your salon. Very cosy in Arctic waters.

The challenge with heating a cat vs a mono is that you really have 3 large areas to heat. The good news is that if you heat the hulls, the saloon will take care of itself due to convection. In the interests of simplicity we put a Dickenson Newport in the starboard hull. On it's lowest setting it will heat the starboard hull and saloon nicely and avoids all the installation, cost and maintenance issues of a forced air heater. Plus, it's really cool to have a fireplace on your boat! Before we head for high latitudes again we will put another in the port hull, mainly to help with condensation.

Just as important as the type/brand of heater you choose is the amount of insulation, especially with a cat and the Artic air flowing under your bridge deck. You will need to install some sort of insulation anywhere/everywhere you have access to the skin. If you don't, you will have a very difficult time trying to keep it warm regardless of the heater you will also have tremendous issues with condensation without insulation on the skin. Most cats that I have been on just have some sort of carpet glued to the fiberglass, which is adequate in temperate climates but not so much in cold climates.

Good luck!
Tom

Most cats these days are built using foam core construction which acts as an excellent insulator.

I can't comment on this directly, but if you are interested in good info on anything related to high latitude cruising you should check out Attainable Adventure Cruising website. Incredible amount of good info and very well presented.

Personally we have had both Webasto and an Eber. No bad experience with either, but most satisfied with the latter. - but that could just be that the models improve during the years. The sound insulation is better on the last one.

I hear the worst thing to do is to buy a heater that is too big for the job, better to have smaller unit running "hard" and doing a clean burn, than a large heater creating sot on the burner.

In anycase on a previous boat, the former owner had also installed a heat exchanger, so you could utilise the engine heat, as in a car. Saved some diesel when motering - was very content with this solution. (only had mono h.)

Best regards - ColinNorway - not really artic, but October sailing can be pretty cold...

A point to think about is that all these heaters require fuel. Up north it can be a long way between fuel stops and the combo of lots of deep fjords and light winds means a fair bit of motoring.
Lots of folks who live by the shore rely on beach-wood, there is tons on every beach and all you need is an axe. Fitting a log burner as a backup and for a lovely cosy heat is worth thinking of, after all whoever heard of curling up on a bearskin rug in front of the eberspacher!!

A point to think about is that all these heaters require fuel. Up north it can be a long way between fuel stops and the combo of lots of deep fjords and light winds means a fair bit of motoring.
Lots of folks who live by the shore rely on beach-wood, there is tons on every beach and all you need is an axe. Fitting a log burner as a backup and for a lovely cosy heat is worth thinking of, after all whoever heard of curling up on a bearskin rug in front of the eberspacher!!

The salt in beach wood will corrode the heater and the stack if you don't have a place to store the wood and have it flushed by rain for a couple of years.